Whole Home Mixing Valve

[Dave K.]

Came across this nifty item out on inspection this last week. The house was new construction in Oro Valley a suburb of Tucson. Turns out  these whole home mixing valves are finding their way in new home builds in some townships. I was curious on its function and wanted to share my findings.  The mixing valve has 3 distinct benefits:

1. Allows for higher temperatures in the hot water tank, thus extending available hot water. 

2. Prevents bacteria growth ( Legionella ) when the hot water tank is set to 140 to 180 degree F. 

3. Less fear of scalding water at the shower, tub, and sink. 

** Source Honeywell   

 

Honeywell.pdf

[Marc]

I've gotten to 65 without ever suffering any consequences from hot water not above 120 degrees and since only the spouse and I live in our house, equipped with a 30 gallon heater, this mixer thing is just something else that can go wrong.

[Tom Raymond]

Legionella in water heaters is a very low risk. One I believe is largely overblown. 

[hausdok]

They've been around for about 15 years in the Seattle/Bellevue/Redmond area of Washington

[Jim Katen]

They've used them here for quite a while as well. I think it's silly to put them on the whole house. They're best used on the lines that lead to tubs with separate hot & cold valves or to all the tub & shower valves. Then you can guarantee 120-degree (or less) hot water to those fixtures while having hotter water to things like the washer &  dishwasher.